Filter cartridge, filtering face mask and method for manufacturing

Abstract

The invention relates to a filter cartridge for an air filtering device, in particular for a filtering face mask and a method for manufacturing a filter cartridge, comprising a stiff cup-shaped casing having a bottom and a circumferential sidewall extending at least section-wise parallel to one axis, a stiff discoidal lid and a filter bed of loose filter material compressed between the lid and the casing, the lid and the bottom containing each at least one through-hole so that air to be filtered passes through the filter bed, and at least one of the lid and the bottom being curved to at least one direction, whereby the lid is at least essentially arranged within the casing, the outermost contour of the lid close-fitting to the inner contour of the sidewall, and fixed thereto by a direct connection, particularly by a non-detachable connection.

The invention claimed is: 
     
       1. Filter cartridge ( 1 ) for an air filtering device, in particular for a filtering face mask ( 15 ), comprising a stiff cup-shaped casing ( 2 ) having a bottom ( 4 ) and a circumferential sidewall ( 5 ) extending at least section-wise parallel to one axis, a stiff discoidal lid ( 3 ) and a filter bed ( 14 ) of loose filter material compressed between the lid ( 3 ) and the casing ( 2 ), the lid ( 3 ) and the bottom ( 4 ) containing each at least one through-hole ( 67 ) so that air to he filtered passes through the filter bed ( 14 ), and at least one of the lid ( 3 ) and the bottom ( 4 ) being curved to at least one direction, whereby the lid ( 3 ) is at least essentially arranged within the casing ( 2 ), the outermost contour of the lid ( 3 ) close-fitting to the inner contour of the Sidewall, ( 5 ), and fixed thereto by a direct connection, particularly by a non-detachable connection. 
     
     
       2. Cartridge according to  claim 1 , characterized in that the lid is fixed to the casing ( 2 ) by form closure or material connection ( 40 ). 
     
     
       3. Cartridge according to  claim 1 , characterized in that the material connection ( 40 ) that particularly extends along the whole circumference of the lid ( 3 ) is a weld  20  connection. 
     
     
       4. Cartridge according to  claim 2 , characterized in that the form closure comprises at least one plastically deformed portion of at least one of the casing ( 2 ) and the lid ( 3 ). 
     
     
       5. Cartridge according to  claim 1 , characterized in that at least one plastically deformed portion of the casing ( 2 ) is plastically deformed such that it protrudes to the inside of the casing ( 2 ) acting upon the lid ( 3 ) to maintain the loose filter material compressed between the lid ( 3 ) and the easing ( 2 ). 
     
     
       6. Cartridge according to  claim 5 , characterized in that the plastically deformed portion is a plastically deformed portion of the inner surface of the sidewall ( 5 ) or a bent projection that protrudes from a free end of the sidewall ( 5 ). 
     
     
       7. Cartridge according to  claim 1 , characterized in that the lid ( 3 ) contains a circumferential protrusion ( 13 ) that protrudes essentially parallel to said axis in at least one direction. 
     
     
       8. Cartridge according to  claim 7  characterized in that the lid ( 3 ) extends parallel to the bottom ( 4 ) such that the distance between the lid ( 3 ) and the bottom ( 4 ) is at least essentially constant and that the filter bed ( 14 ) has an at least essentially uniform height. 
     
     
       9. Cartridge according to  claim 8 , characterized in that the surfaces ( 8 , 9 ) of the lid ( 3 ) and the bottom ( 4 ) facing each other are each covered by a fleece element ( 10 , 11 ) extending across the at least one respective through hole ( 6 , 7 ). 
     
     
       10. Filtering face mask, in particular compact face mask, comprising a mask body ( 14 ) adapted to fit over the nose and mouth of a person and at least one filter cartridge ( 1 ) that is arranged in an orifice ( 20 ) of the mask body ( 16 ), characterized in that the filter cartridge ( 1 ) comprising a stiff cup-shaped casing ( 2 ) having a bottom ( 4 ) and a circumferential sidewall ( 5 ) extending at least section-wise parallel to one axis, a stiff discoidal lid ( 3 ) and a filter bed ( 14 ) of loose filter material compressed between the lid ( 3 ) and the casing ( 2 ), the lid ( 3 ) and the bottom ( 4 ) containing each at least one through-hole ( 6 , 7 ) so that air to be filtered passes through the filter bed ( 14 ), and at least one of the lid ( 3 ) and the bottom ( 4 ) being curved to at least one direction, whereby the lid ( 3 ) is at least essentially arranged within the casing ( 2 ), the outermost contour of the lid ( 3 ) close-fitting, to the inner contour of the Sidewalk ( 5 ), and fixed thereto by a direct connection, particularly by a non-detachable connection. 
     
     
       11. Filtering face mask according to  claim 10 , characterized in that the orifice ( 20 ) is designed as receptacle ( 18 ) in which the cartridge ( 1 ) is held with its outer contour of the sidewall in a sealed manner such that air to be filtered passes through the filter bed ( 14 ) of the filter cartridge ( 1 ) and preferably having at least one abutting shoulder ( 21 ) for aligning and supporting the cartridge ( 1 ). 
     
     
       12. Filtering face mask according to  claim 10 , characterized in that between the abutting shoulder ( 21 ) and the cartridge ( 1 ) a cup-shaped support element ( 22 ) comprising at least one opening ( 23 ) is arranged essentially spaced apart to the bottom ( 4 ). 
     
     
       13. Method for manufacturing a filter cartridge for air filtering  15  devices, in particular for a filtering face mask, comprising the following steps:
 providing a stiff cup-shaped casing ( 2 ) having a bottom ( 4 ) and a circumferential sidewall ( 5 ) extending at least section-wise parallel to one axis, the bottom ( 4 ) having at least one through-hole ( 6 ), 
 pouring out a desired amount of loose filter material into the casing ( 2 ) onto its bottom ( 4 ), providing a stiff lid ( 3 ) with its outermost contour close-fitting to the inside of the sidewall ( 5 ) of the casing ( 2 ) and having at  25  least one through-hole ( 7 ), 
 the lid ( 3 ) and/or the bottom ( 4 ) are curved into at least one direction, 
 pressing the lid ( 3 ) at least essentially into the casing ( 4 ) until the filter material is compressed to a uniform filter bed ( 14 ) where the filter material is distributed evenly across the cartridge ( 1 ), fastening the lid ( 3 ) to the casing ( 2 ) providing a direct connection, particularly a non-detachable connection between the lid ( 3 ) and the casing ( 2 ). 
 
     
     
       14. Method according to  claim 13 , characterized in that the non-detachable connection is provided by welding the lid ( 3 ) at least partially along the circumference of the lid ( 3 ) to the sidewall ( 5 ) of the casing ( 2 ). 
     
     
       15. Method according to  claim 13  characterized in that the non-detachable connection is provided by plastically deforming a portion of at least one of the casing and the lid ( 3 ).